Liquid metal rotary heat exchanger



Aug. 16, 1966 A. SABATIUK LIQUID METAL ROTARY HEAT EXCHANGER 5Sheets-Sheet 1 Filed Feb. 11, 1964 INVENTOR ANDREW EAEIATIUK ATTORNEYAug. 16, 1966 A. SABATIUK 3,265,564

LIQUID METAL ROTARY HEAT EXCHANGER 3 Sheets-Sheet 2 Filed Feb. 11, 1964INV NTOR. ANDREW EKEATIUK ATTORNEY Aug. 16, 1966 A. SABATIUK LIQUIDMETAL ROTARY HEAT EXCHANGER 5 Sheets-Sheet 5 Filed Feb. 11, 1964 i l v mIv Qn ww 7/ /l|.|W HlM\l l// V N7 /A vm D D W M \Nw Nw \yw H M M S C CHn l l N Hill! "u H "Ilillflh Lilli HFIIIIJIIIIIhHHH lhrlllhnh "4 N a i1 HEBMEIEHEBEEHEm -a Maw Y INVENTOR. AN DREW EAEIATILM Y B *6 3mm LEI IE ATTEIRNEY United States PatentO This invention relates to gas turbineengines and in particular to a means for utilizing the heat of theexhaust gases to reduce the fuel consumption.

Gas turbine engines are being used in increasing quan- 1 tities forauxiliary power drives, generation of electricity, pumping of liquidsand gases,,and as prime movers in aircraft, marine and automotivevehicles. However, one of the principal disadvantages of the gas turbineengine lies in'its poor fuel economy at part-power load conditions. Ithas long been recognized that the use of regenerativecycles in gasturbine engines presents a promising means of achieving good part-loadfuel economy. In the regenerative-cycle, heat from the exhaust gasesfrom the gas turbine engine is removed and transferred to the incomingair prior to introduction of said air into the combustion zone. By thismeans, the air for combustion is preheated which thereby improves thecombustion process with a resulting reduction in the fuel consumption.In the past, however, the conventional heat exchange systems used forcarrying out the regenerative-cycle have suffered from serious drawbacksin that they were of excessive weight and volume resulting in cumbersomeand awkward engine configurations and further were of complex design.

It is a prime object of the present invention to provide a novel andimproved heat exchanger of the rotary type for a gas turbine enginewhich is relatively light in weight, simple in construction and hasimproved heat exchanging effectiveness. The invention is generallycarried out by providing a rotary heat exchanger which is rotatablerelative to the compressor and turbine of the gas turbine engine and isprovided with a plurality of circumferentiallyspaced hollow blade-likemembers each of which has a liquid metal sealed therein. The liquidmetal in each of the blade members is acted upon by centrifugal forcesdue to the rotation of the rotary heat exchanger which urges the liquidmetal to flow radially outwardly relative to its respective blademember. The radially outer portion of each of the blade members isexposed to the flow of the relatively hot exhaust gases for flowthereover while the radially inner portion of each blade member isexposed to the fiow of the relatively cool compressed air for flowthereover. This results in variation in the temperature of the liquidmetal sealed in the blade member and therefore the centrifugal forces onthe different density portions causes circulation of the liquid metal.If the exhaust gases and compressor air flow are in opposite directionsrelative to the axis of rotation of the blade members, then the liquidadjacent one edge .of each blade member becomes relatively warm comparedto the temperature adjacent to the other edge of the blade memberwhereby in response to the centrifugal forces, the liquid will flowradially outwardly along the cooler edge and radially inwardly along itshotter edge. Thus, there will be a circulation of the liquid metal ineach blade member between its radially outer and inner portions whereinheat will be absorbed by the liquid metal in the radially outer portionfrom the exhaust gases and given oft by the liquid metal to therelatively cool compressed gas in the radially inner portion. Therefore,the compressed gases introduced into the combustion zone will bepreheated prior to mixture with the fuel and combustion thereof whichwill result in a more complete burning of the fuel-air mixture,particularly during part-load operation, with a resultant 3,266,564Patented August 16, 1966 improvement in the specific fuel consumption ofthe engine over the entire power range.

Accordingly it is one object of the invention to provide a novel andimproved heat exchanger mechanism for utilizing heat in the exhaustgases to preheat the combustion air and more particularly it is anobject of the invention to provide such a novel and improved heatexchanger mechanism for a gas turbine engine.

It is a further object of the invention to provide a rotary heatexchanger which is relatively simple in construction with improvedoperating performance.

It is still another object of the invention to provide a rotary heatexchanger which is relatively simple in construction with improvedoperating performance.

It is still another object of the invention to provide a rotary heatexchanger having a heat transfer liquid sealed therein under freeconvection circulation in response to the centrifugal forces on saidliquid.

Other objects and advantages of the invention will become apparent .onreading the following detailed descrip tion withthe accompanyingdrawings wherein:

FIG. 1 is an axially sectional view of a gas turbine engine embodyingthe present invention,

FIG. 2 is an enlarged partial sectonal view of the rotary heat exchangerof the invention, as viewed from the exhaust end of FIG. 1, 5

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2 showing theliquid metal circulation path,

FIG. 4 is a sectional view taken along line 44 of FIG. 3, and showing asingle element of the rotary heat exchanger of the invention,

FIG. 5 is a sectional view taken along line 5-5 of FIG. 3; and

FIG. 6 is a schematic view of the air flow in and out of the rotary heatexchanger of the invention.

Referring now to FIG. 1 of the drawing, a gas turbine engine isschematically illustrated at 10 and comprises a duct-like housing 12having an air compressor 14 journaled within said housing adjacent toits forward end. The air compressor 14 receives air through an annularair inlet 16 and delivers compressed air to a combustion chamber 18where said compressed air is mixed with fuel supplied for examplethrough nozzles 20 for combustion therein. The resulting combustiongases are directed by a nozzle or guide vane structure 22 which maycomprise a plurality of stator blades, to the rotor blades 24 of aturbine rotor 26 for driving said rotor. A shaft 28 drivably connectsthe turbine rotor 26 with the air compressor 14 and in addition isconnected through a suitable reduction gear box 27 to a thrust producingair propeller 25. Therefore, it will be seen that the propellers will bedriven by the turbine rotor 26 for providing the gas turbine engine witha forward propulsive thrust. The gas turbine structure so far describedis conventional and it should be understood that the invention may beembodied in gas turbine engines other than the turbo-prop typeillustrated.

As statedabove, the primary purpose of the invention is to provide anovel and improved heat exchanger mechanism, Referring again to thedrawings, a heat exchanger mechanism 30 of the rotary type isillustrated as being supported for rotation relative to the compressor14 and the turbine rotor 26. The rotary heat exchanger 30 may besupported on an annular stationary housing member 32 surrounding theshaft 28 and has suitable bearings 34 and 36 between said annular member32'and the hub portion 38 of the rotary heat exchanger 30. The bearings34 and 36 support the rotary heat exchanger for end thrust andgyroscopic forces acting on said rotary heat exchanger.

The rotary heat exchanger 30 in itself comprises a plurality ofcircumferentially-spaced, radially-extending blade elements 40. Each ofthe blade elements 40 is hollow and is filled with a liquid metal suchas sodium or the like and is sealed permanently. Some inert gas may alsobe contained in the hollow space in each of the blade elements 40 topermit expansion of the liquid metal. The interior of each of the bladeelements 40 is provided with bafiles or partitions 42 which formcirculation passages for a liquid metal. The partitions 42 may be formedin the interior of the blade elements 40 by crimping the blades withalternate crimps on opposite sides thereof. It will also be apparentthat the partitions 42 serve to prevent high pressure gas fromcollapsing the hollow blade members 42 due to a differential in gaspressure on each side of the blade elements. The blade elements 40 areeach suitably fixed to the rotary heat exchanger mechanism hub portion38 through a slot arrangement in the hub portion 38 which receives anenlarged portion 44 on each of the blade elements (FIGS. 2-4). A shroudinterconnecting the radially-outer portions of the blade members mayalso be provided to provide additional support to the heat exchangerblade elements 40, if necessary.

As further illustrated in FIGS. 24, each of the blade elements isprovided with a plurality of axially-extending, radially-spaced finmembers 46 which provide for heat transfer between the liquid metal inthe interior of the blade elements 14 and the gases which pass over saidfin elements 46. Annular gas seals 48 and 50 are provided at each axialend of the heat exchanger 30, respectively, in a gas seal housingstructure 52 and 54, respectively, which support said seals 48 and 50for sealing engagement against annular housing portions 56 and 58(FIG. 1) adjacent each axial end of the heat exchanger 30, respectively.

The seal housing structure 52 and 54 may be formed by plates 68 and 70suitably secured to the blades 40 or fins 46, as by brazing or the like,with the plates being formed to provide a box-like housing at each axialend of the heat exchanger 30 and having an opening therein to permit theseal members 48 or 50 to protrude therefrom. A movable gas seal piece isprovided in each of the seal housings 52 and 54 with said seal piecesextending slightly circumferentially beyond the width of each blademember its fins and, when the heat exchanger 30 is assembled, the sealpieces of each blade member mate with the seal pieces carried by anadjacent blade element to form the continuous annular seals 48 and 50.

The movable gas seals 48 and 50 may be biased into engagement with theengine housing portions 56 and 58 by springs 64 and 66 (FIG. 3) or thelike. However, the seal members 48 and 50 may be carried by the housingportions 56 and 58 for sealing against an annular portion of the rotaryheat exchanger mechanism 30 instead of the arrangement shown. Asillustrated in FIGS. 2, 4 and 5, the plates 68 and 70 extend in acircumferential direction so that they are immediately adjacent a platemember 68 or 70 extending from an adjacent blade element 40 in theassembled unit and in the region of the seal housings 52 and 54 theplate members 68 and 70 are in abutting relationship so that the gasseal housings 52 and 54 for each blade member 40 at each axial end ofthe heat exchanger mechanism 30 mate to form a continuous annularhousing, as partially illustrated in FIG. 2. The metal plates 68 and 70from each of the blade elements 40 overlap a circular member 72 whichalso extends over the entire axial dimension of each of the bladeelements 40 to form a radial seal between the metal plates 68 and 70 andsaid circular member 72. The circular members 72 are each formed from anassociated portion of a separation plate 74 which is positionedintermediate of each of the blade elements 40 as viewed in thecircumferential direction and also extend over the entire axial lengthof the heat exchanger mechanism 30. The separation plates 74 serve toprevent the blade elements 40 from bulging as a result of pressuredifferentials by allowing them to mutually support each other throughsaid separation plates rather than letting the fin members of each ofthe blade members 40 mesh together. As illustrated in FIG. 2, theseparation plates 74 are provided in the radially upper portion of theheat exchanger mechanism 30 which is the high pressure side of saidmechanism. However, it should be understood that the seal meansillustrated is only meant to be exemplary of a type of seal means whichmay be used with the present invention and the invention is not intendedto be limited to the specific seal means shown and other suitable sealmeans such as a labyrinth type seal may be used.

It will be apparent from the above description that the movable sealmembers 48 and 50 and their related construction and the metal plates 68and 70 with the circular section members 72 serve as a partition meansto divide the rotary heat exchanger 30 into a radially inner portion anda radially outer portion with each of said portions being sealed fromone another by the prior-mentioned construction so that gas leakagebetween the two portions will be prevented.

Referring to FIGS. 1 and 6, a row of stator blades 76 is positionedintermediate the compressor 14 and the rotary heat exchanger mechanism30 with said stator blades 76 being disposed so as to provide a hightangential component to the axial flow of air (solid arrows in FIG. 1)leaving the compressor 14. This high tangential component of compressorair is directed at the blade elements 40 of the rotary heat exchangermechanism 30 and will impart a rotation to said heat exchanger mechanismrelative to the compressor 14 and the turbine 26 with the velocity ofsaid rotary heat exchanger being relatively low as compared to thevelocity of the compressor, for example, due to the fact that therelative velocity of the rotary heat exchanger will be of a magnitudeequal to the tangential component of the compressor air flow. Thisrelatively low flow velocity of the air relative to the rotor bladeelements 40 is favorable for effective heat transfer between the liquidmetal in the hollow blade elements 40 and the air passing over thesurfaces of said blade elements 40. Means may be provided for adjustingthe angle of the stator blades 76 relative to the axial flow of air fromthe compressor 14 to thereby change the tangential component of the airflow relative to the rotor blades 40 of the rotary heat exchanger. Bythis means the rotational speed of the heat exchanger may be changed andthus the circulation of the liquid metal can be controlled for varyingthe effectiveness of the heat exchanger.

It will be apparent from FIG. 1 that the sealed inner I portiondesignated at 78, of the rotary heat exchanger mechanism 30 has a radialdimension which coincides with the annulus of the compressor exitdownstream of the row of stator blades 76 which is designated at 89. Atthe exit side of the rotary heat exchanger mechanism 30, the radiallyinner portion 78 has a radial dimension which coincides with the annulusof the combustion chamber entrance, designated at 82. Thus, it will beseen that the compressor air, as it leaves the compressor, has a sealedflow path through the radially inner portion 78 of the rotary heatexchanger mechanism and into the combustion chamber 18. A row of statorblades 84 is provided at the discharge end of the rotary heat exchangermechanism 30 or in other words upstream of the combustion zone 18 andsaid stator blades 84 are disposed so as to return the tangential flowof air from the heat exchanger mechanism 30 to an axial flow prior toits entrance into the combustion chamber 18. Therefore, referring toFIG. 6, it will be seen that upstream of the rotary heat exchangermechanism 30 or the blade elements 40 a row of stator blades 76 isdisposed so as to receive the compressor air C and to provide atangential component, AV (Absolute Velocity), from the axial flow ofcompressor air, designated RV (Relative Velocity) for imparting rotationto the rotary heat exchanger mechanism 30, designated RR, and a secondrow of stator blades 84 is positioned downstream of the rotary heatexchanger mechanism 30 to return the tangential component, AV, to anaxial flow designated C. As also illustrated-in FIGS. 1 and 6, thecombustion gases T (dotted arrow in FIG.- 1) which have an axial flowupon discharge from the turbine 26, are directed through a row of statorblades 85 prior to entry through the portion 88 of the heat exchangerwith said blades 85 being disposed so as to provide a tangentialcomponent AV which acts on the blades 40 to aid in rotating the heatexchanger mechanism in a manner similar to the gases flowing through theheat exchanger portion 78. A row of stator blades 87 is provided at thedownstream end of the heat exchanger portion 88 to return the tangentialcomponent AV to an axial flow, designated by arrow T. Rotation of themechanism 30 may also be provided by the blade elements 40 alone forthis purpose by orienting them so as to have an angular relationshiprelative to the flow of gases through each portion 78 and 88. It shouldbe understood that the invcntion is not limited to the means illustratedfor imparting rotation to the rotary heat exchanger mechanism 30 andother means may be used such as, a mechanical drive geared from theturbine shaft 28, a drive imparted from the turbine exhaust orcombustion gases instead of the compressor gases, or a bleed flow may betaken from either the compressor or exhaust gases to drive a separateturbine coupled to the rotary heat exchanger mecha- IllSm.

An annular duct 86 having an opening downstream of the turbine 26 isprovided for receiving the combustion gases discharged from said turbine26 (dotted arrows in FIG. 1) and directing said gases in a directiontoward the upper portion 88 of the rotary heat exchanger mechanism 30.The duct 86 has a discharge opening which substantially coincides withthe radical dimension of the upper portion 88 of the rotary heatexchanger mechanism so that the combustion gases will be directedthrough the upper portion 88 of the rotary heat exchanger mechanism andwill be discharged therefrom into an annular duct 90 where thecombustion gases will then be directed toward the exhaust end of theengine for discharge through an exhaust nozzle (not shown) and into thesurrounding atmosphere. It will be seen, therefore, that the relativelycold compressor air will be directed through the rotary heat exchangermechanism 30 in one direction and the relatively hot combustion gaseswill be directed through said rotary heat exchanger mechanism 30 in anopposite direction to the compressor air. FIG. I is merely illustrativeof a system of ducts for directing the compressor air and combustiongases through the rotary heat exchanger mechanism and it should beunderstood that other configurations of duct work may be used withchanges in the basic design of the gas turbine engine such as, forexample, having the compressor at the rearward portion of the engine andthe turbine at the forward portion.

FIGS. 1 and 3 illustrate the circulation of the liquid metal within thehollow blade elements 40. With the rotary heat exchanger mechanism 30rotating about the axis A-A the liquid metal sealed within the hollowblade elements 40 will be acted upon by a radially outwardly directedcentrifugal force designated at CF in FIG. 3. As the hot combustiongases, designated by the arrows T, pass through the upper portion 88 ofthe rotary heat exchanger mechanism 30 in one direction heat will betransmitted from said hot gases to the liquid metal within the hollowblade elements 40. As the relatively cold compressor gases flow in theopposite direction through the lower portion 78 of each blade element40, heat will be transmitted from the liquid metal to the compressorgases. It will be apparent that the liquid metal at the axial end of theheat exchanger mechanism in both the portions 78 and 88 adjacent thecompressor will be at a relatively lower temperature than the liquidmetal in both portions 78 and 88 at the axial ,end of the heat exchangeradjacent the combustion chamber 18. Thus, there will be a differentialin temperature and density of the liquid metal at each axial end of theheat exchanger and due to this differential, the higher temperature,lower density liquid metal at the combustion zone end of the heatexchanger, or the rearward portion,

will flow radially inwardly along the rearward wall and.

relatively higher temperature and lower density liquidmetal containedtherein than the preceding path. Thus, there will be a differential intemperature and density of the liquid metal in each of the axiallyadjacent flow paths formed by the partitions 42 which will result in theliquid metal flow circulating in and out of the paths and guided by thepartitions 42, as illustrated in FIGS. 1 and 3 with the flow being fromfront to rear in the radially outward portion 88 and rear to front inthe radially inner portion 78.

From the above, it will be seen that the liquid metal, when it reachesthe radially outward portion 88 of the rotor, will pick up heat from thehot combustion gases passing over this portion and as the liquid metal,which has been heated in the radially outward portion 88, flows to'theradially inward portion 78 of the rotor, heat will be transferred fromsaid liquid metal to the relatively cold compressor air designated byarrows C in FIG. 3, passing through this region. It will be apparentthat the liquid metal within each of the rotor blade elements 40, duringoperation, has a free convection circulation due the heat transfer fromthe hot combustion gases to the liquid metal and from the liquid metalto the relatively cold compressor air. from the hot combustion gases topreheat the relatively cold compressor air prior to its entrance intothe combustion chamber 18.

As is well known, raising the temperature of the compressor air as itenters the combustion chamber for c0mbustion therein permits a moreeconomical use of the fuel mixed with said compressor air, particularlyat the part-load operating conditions. It should be particularly notedthat the heat transfer from the hot combustion gases to the compressorair is brought about in complete absence of any pumps or othermechanical means for creating circulation of the heat transfer medium.It should also be noted that the device is a steady flow device usingseparate paths for the hot and cold gases which as a result simplifiesthe scaling mechanisms between the separate gas fiow paths. Further, thecirculation of the liquid metal within the blade elements 40 isrelatively simple and does not require any two-directional or flowreversal of the liquid metal in order to provide the heat transfer fromthe combustion gases to the compressor air. Another advantage of theinvention lies in the fact that no separate storage is required for theliquid metal and therefore the problem of the liquid metal solidifyin atrelatively low temperatures so as to make starting the system ditficultis avoided. It will also be seen that the design of the rotary heatexchanger mechanism will be compact and lightweight. The compactness ofthe rotary heat exchanger of the invention will permit a shorter overallengine configuration which will result in reducing critical speedproblems and weight problems than, as for example, could be accommodatedby a gas to air type heat exchanger.

From the above detailed description, it will be apparent that theinvention provides for a novel and improved rotary heat exchangermechanism which is compact, light in weight and has improved efficiencyand economy over heat exchanger mechanisms of the prior art type. WhileIn this manner, heat is transferred I have described my invention indetail in its preferred embodiment, it will be obvious to those skilledin the art, after understanding my invention that various changes andmodifications may be made therein without departing from the spirit orscope thereof. I aim in the appended claims to cover all suchmodifications.

I claim as my invention:

1. A rotary heat exchanger including means for rotating said heatexchanger, said rotary heat exchanger comprismg:

(a) a hub member;

(b) a plurality of circumferentially-spaced heat exchanger elementssecured to said hub member and extending radially theretrom with eachsaid element including a plurality of interconnected substantially-shaped passages extending from one axial end of said element to theother;

(c) partition means disposed intermediate the radial length of saidelements and extending circumferentially between said elements such thatsaid partition means forms the inner wall of a first annular gas flowpath across which the radially outer portions of said elements extendand said partition means with said hub member also forming the outer andinner walls respectively of a second annular gas flow path across whichthe radially inner portions of said elements extend;

(d) a plurality of radially-spaced heat exchange fin members secured toand projecting circumferentially from both the radially inner andradially outer portions of said elements into heat exchange relationshipwith the gases flowing though said flow paths; an

(e) a heat exchange liquid sealed within said elements for circulationthrough said passages in response to centrifugal forces acting on saidliquid due to rotation of said heat exchanger for transferring heatbetween the radially inner and outer portions of said elements.

2. A rotary heat exchanger as recited in claim 1 wherein: Y

(a) said elements have a blade-like configuration and in one of saidannular gas flow paths are angularly disposed relative to the directionof the gas flow through said annular gas flow path so that the gas flowacts on said elements to impart rotation to said rotary heat exchanger.

3. A rotary heat exchanger as recited in claim 1 further comprising:

(a) guide means including at least one interior partition disposedintermediate of the axial limiting walls of each element and extendingradially between both said radially inner and outer portions of saidelement but terminating short of the radial limiting walls of each saidelement for guiding said heat exchange liquid around said interiorpartition between said radially inner and outer portions of said elementduring circulation of said liquid within said element.

4. A rotary heat exchanger as recited in claim 1 wherein:

(a) said heat exchange liquid comprises a liquid metal with said liquidmetal being in a liquid state at least at temperatures above the ambientatmospheric temperature.

5. A rotary heat exchanger as recited in claim 1 wherein:

(a) said partition means includes seal means in sealing relationshipwith an outer body for preventing mixture of the gases in said firstannular gas flow path with the gases in said second annular gas flowpath.

6. A rotary heat exchanger supported in an outer body for transmittingheat from a hot fluid stream to a cold fluid stream with said outer bodyincluding passage means for separately guiding each of said fluidstreams axially in opposite directions relative to each other and alsoineluding means for rotating said heat exchanger, said rotary heatexchanger comprising:

(a) a rotor having a first radial portion disposed in the path of saidhot fluid stream and a second portion radially inward of said firstportion and disposed in the path of said cold fluid stream;

(b) partition means on said rotor intermediate said first and secondportions for dividing said rotor into first and second annular flowpaths;

(c) said rotor including a plurality of circumferentially-spaced heatexchanger elements extending radially outwardly from said second portionthrough said first portion and supported for rotation about the axis ofsaid rotary heat exchanger with each said element including a pluralityof interconnected sub stantially radially oriented liquid conductingpassages disposed in axial relationship from one end of said element tothe other;

(d) a plurality of radially-spaced heat exchange fin elements on theouter surface of said elements in heat exchange relationship with saidhot and cold fluid streams; and

(e) a heat exchange liquid sealed in each of said elements which inresponse to rotation of said rotor and the difference in temperature ofsaid hot and cold fluid streams is caused to circulate through saidpassages of said elements between said first and second portions forabsorbing heat from said hot fluid stream and transmitting heat to saidcold fluid stream.

7. A rotary heat exchanger as recited in claim 6 wherein said heattransfer material comprises a liquid metal with said liquid meta-l beingin a liquid state at least at temperatures above the ambient atmospherictemperature.

8. A rotary heat exchanger as recited in claim 6 further comprising sealmeans on said rotor for sealing engagement with said outer body and saidseal means being disposed so as to provide a gas seal between said firstradial portion and said second portion for preventing mixture of saidhot fluid stream with said cold fluid stream.

9. A rotary heat exchanger as recited in claim 6 wherein each saidelement comprises a blade-like member with each blade-like member havinginterior partitions therein for guiding said heat exchange liquid duringcirculation within said blade-like element.

10. A rotary heat exchanger for use in a gas turbine engine having anouter body including means for directing the compressor air and exhaustgases of said gas turbine engine axially in opposite directions, saidrotary heat exchanger comprising:

(a) a rotor including a hub member and including means for rotating saidheat exchanger relative to said gas turbine outer body;-

(b) a plurality of circum ferentially-spaced radially extending hollowelements secured to said h-ub memher for rotation therewith;

(c) partition means disposed intermediate the radial length of saidhollow elements and extending between each of said hollow elements suchthat said partition means separates said rotor into first and secondradial portions each of which defining a separate gas flow path throughsaid rotor with said first radial portion being disposed in the path ofsaid gas turbine combustion gases and said second radial portion beingdisposed in the path of said gas turbine compressor air;

(d) seal means disposed between said first and second radial portions ofsaid rotor for sealing cooperation between said gas turbine outer bodyand said rotor so is to provide a gasseal between said gas flow P (e) aplurality of radially-spaced heat exchange fin members secured to andprojecting from the outer surface of each said hollow element into heatexchange with the gascs flowing through said gas fiow p (-f) a heatexchange liquid sealed within each of said hol-low elements which inresponse to the centrifugal ior-ces on said liquid generated duringrotation of said rotor and the difference in temperature between saidgas tunbine combustion gases and compressor air circulates within saidhollow elements between said first and second radial portions wherebyheat is transferred from said combustion gases by said liquid to saidcompressor air for preheating said compressor air prior to combustion;and

(g) each said hollow element is provided with partit-ion means in theinterior thereof 'for guiding said heat exchange liquid duringcirculation between said first and second radial portions.

11. A rotary heat exchanger as recited in claim 10 wherein:

(a) said partition means includes at least one radially extendingpartition disposed intermediate the axial limiting walls but terminatingshort of the radially limiting walls of each hollolw element so that theheat exchange liquid circulates radially inwardly along one axiallimiting wall of said hollow element, around said interior portion, tosaid first-mentioned axial limiting wall.

12. A rotary heat exchanger as recited in claim \10 wherein:

(a) said heat exchange liquid comprises a liquid metal.

References Cited by the Examiner UNITED STATES PATENTS 1,739,137 12/1929Gay 165-181 X 2,925,714 2/1960 Cook 60-39.5 1 X 3,007,685 11/1961Hryniszak 165-104 X FOREIGN PATENTS 1,002,570 2/ 1957 Germany.

792,984 4/1958 Great Britain.

ROBERT A. OLEARY, Primary Examiner.

A. W. DAVIS, Assistant Examiner.

1. A ROTARY HEAT EXCHANGER INCLUDING MEANS FOR ROTATING SAID HEAT EXCHANGER, SAID ROTARY HEAT EXCHANGER COMPRISING: (A) A HUB MEMBER; (B) A PLURALITY OF CIRCUMFERENTIALLY-SPACED HEAT EXCHANGER ELEMENTS SECURED TO SAID HUB MEMBER AND EXTENDING RADIALLY THEREFROM WITH EACH SAID ELEMENT INCLUDING A PLURALITY OF INTERCONNECTED SUBSTANTIALLY U-SHAPED PASSAGES EXTENDING FROM ONE AXIAL END OF SAID ELEMENT TO THE OTHER; (C) PARTITION MEANS DISPOSED INTERMEDIATE THE RADIAL LENGTH OF SAID ELEMENTS AND EXTENDING CIRCUMFERENTIALLY BETWEEN SAID ELEMENTS SUCH THAT SAID PARTITION MEANS FORMS THE INNER WALL OF A FIRST ANNULAR GAS FLOW PATH ACROSS WHICH THE RADIALLY OUTER PORTIONS OF SAID ELEMENTS EXTEND AND SAID PARTITION MEANS WITH SAID HUB MEMBER ALSO FORMING THE OUTER AND INNER WALLS RESPECTIVELY OF A SECOND ANNULAR GAS FLOW PATH ACROSS WHICH THE RADIALLY INNER PORTIONS OF SAID ELEMENTS EXTEND; (D) A PLURALITY OF RADIALLY-SPACED HEAT EXCHANGE FIN MEMBERS SECURED TO AND PROJECTING CIRCUMFERENTIALLY FROM BOTH THE RADIALLY INNER AND RADIALLY OUTER PORTIONS OF SAID ELEMENTS INTO HEAT EXCHANGE RELATIONSHIP WITH THE GASES FLOWING THROUGH SAID FLOW PATHS; AND (E) A HEAT EXCHANGE LIQUID SEALED WITHIN SAID ELEMENTS FOR CIRCULATION THROUGH SAID PASSAGES IN RESPONSE TO CENTRIFUGAL FORCES ACTING ON SAID LIQUID DUE TO ROTATION OF SAID HEAT EXCHANGER FOR TRANSFERRING HEAT BETWEEN THE RADIALLY INNER AND OUTER PORTIONS OF SAID ELEMENTS. 